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LMX2820: Vtune voltage keep at same level with all different frequency ourput.

Part Number: LMX2820


Hi,

I have two question:

1. I checked Vtune voltage with different output frequency from 6GHz to 11GHz. based on my understand, the "output frequenct=Vtune * KVCO + VCO center frequency". so I expect I can see some different Vtune voltage with different output frequency, but why I only see the Vtune equal to about 1.35V for all different VCO output freqyuency? is there anything I understanding wrong?

2. I can see different VCO core will cover different frequency range. for example. the VCO 1 will cover the output frequency from 5650MHz to 6350Mhz,so the range is 700Mhz.  I see the max Vtune is 2.5V for internal VCO mode. and the min KVCO is 115MHz/V. then correct me if I am wrong: 2.5V * 115Mhz=287.5MHz. then how the VCO1 can cover 700MHz frequency range?

Thanks for your answer in advance!

Wei